bo 
Is 
PLATE 55, 
1-2. Pourtalesia Tanneri A. Ag.; Station 3431. 
Seen from the actinal side. 
The same, seen in profile, facing the left posterior ambulacrum. 
3-5. Plexechinus cinctus A. Ag.; Station 3424. 
Seen from the actinal side. 
The same, seen from the abactinal side. 
The same, seen in profile, facing the left posterior ambulacrum. 
6-8. Aérope fulva A. Ag.; Station 3361. 
Seen from the actinal side. 
The same, seen from the abactinal side. 
The same, seen in profile, facing the left posterior ambulacrum. 
9-10. Homolampas hastata A. Ag. 
Seen from the actinal side. 
The same, seen from the abactinal side. 
All figures natural size. 
